The invention relates to a suspension bar for an anode or cathode sheet.
In the electrolysis process, the purity of metals is increased by means of anodes, cathodes, an electrolyte and electrical power The cathodes consist of a thin sheet of the same metal as the one which has to be purified In some cases, the anodes are insoluble sheets, but generally the anodes are manufactured from the metal to be purified As the result of the passage of current, the last named anodes will go into solution, while the metal ions of the metal to be purified will deposit at the cathode as a result of which the cathode sheets will start to grow. The cathode or anode sheets may be rather heavy. The sheets are suspended on suspension bars which also serve as current conductors. The suspension bars should therefore have good mechanical properties especially in relation to the bending load.
Because the suspension bars also serve as current conductors and, for economic reasons, the electrolysis takes place with a high amperage and a low voltage, the suspension bars should preferably be manufactured from copper in order to keep the current losses as low as possible. For this purpose, hard copper is used; the tensile strength of copper is increased by plastic deformation. If such hard copper is heated, the tensile strength will fall off considerably. The tensile strength of copper is lowest in the soft state.
If the current strength is increased in the electrolysis process, copper suspension bars may pass into the soft state as a consequence of the development of heat, as a result of which they may easily deform owing to excessive loading during electrolysis or rough handling when the sheets are being replaced, as a result of which the electrolysis process can no longer proceed ideally on further use or it may not even be at all possible to use said suspension bars any longer.